The Darkness within
by KatLokidottir
Summary: "The serum amplifies everything that is inside; so good becomes great, bad becomes worse." What if it wasn't Tony who tried to negotiate with Loki? When Captain America volunteers to go in his stead, he has no idea what he's getting himself, and the world, into. Bad!Steve AU. Intended to be a one-shot, but may extend if I get some love from readers. R&R and please, no flaming.
1. Chapter 1

The tension in the air was palpable as Steve apprehensively looked down from the aircraft hovering over New York. True, he had done this before, parachuting from a plane, and in much worse conditions with the enemy trying desperately to shoot him down while he was armed with only a thin wooden shield, but he was still nervous.

"You're sure that I'm directly above the walkway?" Steve asked the pilot as he peered down at Stark Tower.

"Yes," replied the pilot with an exasperated sigh.

"Are you posit-" Steve started, only to be shoved out the hatch by an impatient red-headed assassin.

She watched as he landed gracefully on the balcony, the parachute momentarily billowing in the wind before collapsing.  
Steve quickly unclipped the parachute, shooting an angry glare towards the rapidly disappearing quinjet before brushing himself off. He looked up, turning to see Loki staring at him from the opposite balcony, a bemused smile on his face.

Simultaneously, they both began walking towards the lounge, sizing each other up as they went. Steve looked away as he entered the lounge area, quelling the small panic that was bubbling in the pit of his stomach. He was unarmed in a room with a sociopathic and psychotic god bent on world domination. Fun times.

"Please tell me you're going to appeal to my _humanity_," scoffed Loki as Steve stepped behind the bar.

"Actually, I'm going to threaten you."

"You? Threaten me? Without so much as your shield?" sneered the god.

"Eh, it's seen a bit of mileage and you've got the 'glowstick of destiny,'" replied Steve nonchalantly. Loki smiled slightly at this, glancing down at his scepter.

"You want a drink?" asked Steve, offering one of Tony's many bottles of spirits as if he were talking to an old friend rather than a villain he was scheduled to fight. Loki just stared at him, the corners of his mouth tilted slightly upwards.

"No? Well, I'm not too into alcohol either," continued the Captain, walking over to one of Tony's ultra-plush couches that probably sold for more than he would.

Loki stepped up to the panoramic window, gazing out over Manhattan.

"Stalling me with your mindless banter won't change anything," Loki said softly. "The Chitauri are coming. What have I to fear?"

"The Avengers."

Loki turned to look at Steve, who was sprawled out on the sofa, in confusion.

"It's what we call ourselves," explained the super soldier. "Sort of like a team. 'Earth's Mightiest Heroes' type thing."

"I've met them," the 'god' replied in a tone that conveyed amused condescension.

Catching the loaded look, the Captain frowned slightly. "Takes us a while to get any traction, I'll give you that one; but, let's do a headcount here: your brother, the demigod, the genius with the iron suit, basically a living legend who kinda lives up to legend, a man with _breathtaking_ anger management issues, a couple of master assassins, and you, big fella. You've managed to piss off every single one of them."

Loki grinned. "That was the plan."

"Not a great plan," replied Steve. "When they come for you, and they will," he said, eyes narrowing slightly, "they'll come for you."

Loki's amused expression morphed into an irritated, threatening one. "I have an army."

"We have a Hulk," retorted the Captain.

Loki feigned surprise. "I thought the beast had wandered off..."

Steve cut Loki off.

"You're missing the point. There's no throne, no way for you to come out on top. Look, _maybe _your army comes and _maybe_ it's too much for us, but it's all on you. Because if we can't protect the earth, you can be _damn_ sure we'll avenge it," finished Steve confidently.

For a moment the room was deathly quiet, then Loki's voice filled the room.

"Is that so? You're going to avenge the earth?" he asked, chuckling. "How do you plan on doing that if you're all dead or enslaved, hmm? I suppose you'll use your super strength to break free from whatever is used to restrain you, even Death's own arms. Or, perhaps you plan on bringing out that innate 'goodness' in everyone," he said, his face darkening although his voice kept that amused tone.

Loki began taking slow steps towards Steve.

"What you seem to forget, my dear Captain, is that not only is there an innate goodness, but an equal measure of darkness, of forbidden desires and secrets, of evil. That is how the universe functions, is it not? Light versus dark, constantly at war with one another. That is also the darkest truth of humanity, that one is always dancing along that fine edge between good and bad, temptation ever present. I understand moreso than most, being the very God of Chaos."

Steve found himself beginning to get uncomfortable with the turn the conversation had taken and silently removed his earpiece, shutting it off, as Loki continued on.

"For you, Captain, it is an even thinner edge. 'The serum amplifies everything that is inside; so good becomes great, bad becomes worse.' Is that not what your dear Dr. Erskine said? That darkness inside of you grew as well as the good."

_How the hell does he know what Erskine said? _thought the Captain. His second thought: _finally, someone who realizes the painfully obvious. _

"You play the hero, the very pinnacle of goodness, of innocence. But you want to know what it's like to be on the other side. To have absolute power over someone, to have them kneeling before you, not out of respect, but out of fear. You crave freedom. The freedom to make the wrong decision. The freedom to avoid judgement. The freedom to take power. I can give you that power, Captain. Unlimited power, over the entire world. All you have to do is say so."

Steve's thoughts were in chaos, conflicting emotions battling for dominance. "But my team..."

"Your team?" sneered the god. "Let's see here. An arrogant, ungrateful, selfish genius, who sees you as only a lab experiment. A mindless beast who doesn't even want to be there. An archer who couldn't care less about anyone other than his precious redhead. An assassin, who'd be willing to kill you if ordered without a second thought and who abandoned you here alone with me. And let's not forget the blonde-headed demigod, who tried to pummel you with his hammer for trying to protect said genius."

"My job with SHIELD..."

"SHIELD? The organization who lied to your face many times, who were secretly building weapons of mass destruction, who are composed completely of liars and killers, of spies and mercenaries? The organization that specializes in subterfuge, interrogation, and elimination? Yes, I can see why you'd want to work with them," scoffed Loki.

"You're the god of lies. How can I trust you?"

Loki barked out a laugh. "You can't. But, think about this: you know for a fact that you can't trust your 'teammates' of your precious SHIELD either. And I can offer so much more than they can! They offer a mere feeling of satisfaction for doing what they think is 'right'. I offer you the satisfaction of ruling an entire realm alongside me, the ability to have the world at your feet to do what you wish with it without risk of being judged, of disappointing someone. You can have anything and everything. Just say the word."

A dark smile broke out on Steve's face, a genuine smile.

"I accept."


	2. Chapter 2

Author's Note: Well, I've decided to continue the story. I don't know if this chapter is any good, because, as I said, I originally wasn't planning to continue this, so I'm still working out a longer plotline. Anyways, please read, and REVIEW! :) Reviews are love. On with the show! BTW, this is Loki's POV.

I smiled at the super soldier's response. The very pinnacle of good gone bad. The backbone, the leader of the so-called "heroes," turned with a few words from my silver tongue. I bit back a smirk of satisfaction, instead turning back to the window, hiding my growing elation.

"What's their play?" I ask softly, and the Captain walks slowly over to stand beside me.

He laughed. "They don't have one. Basically, they're gonna wing it. Fight whatever comes out, try to kill as few civilians as possible, and don't die is basically the entirety of the plan. If we have a plan of attack, other than simply attacking, we have an advantage in that way, as well as in numbers."

I turn my head slightly, glancing at him.

"What would you suggest, Captain?"

"I would say that the best way to go about this is probably to send only a few Chitauri out at first, so they underestimate us, while Selvig works on expanding the portal. Once it is decently expanded, we send out a swarm of Chitauri and Leviathins, and the sheer number is likely to overwhelm them."

"What about the green beast?"

"Ah," says the Captain, thinking for a moment. "Stark has a Hulk-buster serum in his lab downstairs. If someone can inject the Hulk with it, he will pass out."

"And the others?"

"Barton and Romanoff will be fairly easy to take out, so the only ones we really need to worry about are Thor and Ton- Stark."

"I'll take care of Thor, Captain. You focus on getting Iron Man out of the picture."

My mind is already racing with ways to disable my brother, the 'mighty' oaf.

"Sir?" says Steve, tentatively.

"Yes, Cap?"

"May I suggest that we not kill them?"

I turn to give him an incredulous, suspicious look.

"What is this? You wish for your old teammates to live? Sentiment," I scoff.

"No, sir, I was just thinking that they would be of more use alive than dead. I mean, having two assassins, a genius and billionaire, and giant green rage monster under your control could come in handy, sir, if not in battle, then perhaps as a ransom or an example to the people."

I consider his suggestion. He has a point. Of course, killing them would be satisfactory, but keeping them, making them mine would be far more useful and satisfying in the long run. I could use my scepter on the assassins, and perhaps the beast, although I do wonder if it will work on Stark.

"Barton told me Stark has a metal heart he calls an arc reactor. Is this true?"

"Yes, sir. It's made of an element created by his father. He calls it Starkium. It actually appears similar to the stone in your scepter."

"Hmm." It sounded similar to the Tesseract from the information I got from Barton, and this new information settles things in my mind. If it is a part of the Tesseract, or composed of the same element, then the scepter will not work on the Man of Iron. But, there are other ways to get him to do what I want, so I'm not too worried.

"Captain."

"Sir?"

"Get the serum you were talking about, and hide it on your person."

"Yes, sir. Is the lab unlocked?"

"Yes, I have disabled Stark's AI. Everything is now under my control within this Tower."

"Thank you." Steve turns on a well-polished heel and heads towards the elevator.

As the doors slide shut, I go through the Captain's suggested plan in my head. Looking for any ways it could backfire, how to fix them. After I am satisfied fully, I think back on the Captain's behavior. Something seems off. I may have a silver tongue, but someone with such ethics should have taken more persuading. Could he be tricking me, attempting to trick the trickster?

Lost in my thoughts, I don't notice the time until the whoosh of the elevator jerks me out of my reverie.

I turn to look at the Captain, a slight frown on my face.

"Sir?" the Captain asks, looking worried.

I disappear from sight for a minute, reappearing directly in front of the (ex?) hero. I grip his throat with an iron grip and slam him against the closed elevator doors.

He may have super strength, but I have godly strength.

His hands lock around my wrists, trying to force his head up to avoid strangulation, eyes wide.

"Loki-"

"If I find out that this is some sort of trick or game, Captain, you will most sincerely regret your decision. I will make you beg for death," I hiss in warning.

"I swear, I'm not! Please-" the Captain gasps, face red.

I give him one more squeeze, then release him onto the floor, panting. I bend down slightly, hooking a finger beneath his chin and forcing his head upwards. He looks up at me, fear and pain still evident in those deep blue eyes, now the color of a roiling sea.

"Do not disappoint me, Captain."

"No, sir," he says softly.

My point made, I offer a hand to the man.

He hesitates, then takes it, and I pull him to his feet, releasing his hand the second he is on his feet again.

"You cannot let the Avengers know you are helping me, Captain."

"I know."

"I know the best way to ensure that."

Before the Captain can even speak, I have him by the throat again, lighter this time, and drag him to the window.

"Stick to the plan, and you will be rewarded," I murmur.

With that, I lift the Captain by the throat and throw him through the glass, watching as he falls towards the pavement below.

A follow or favorite gets you Coulson's Captain America trading cards, a review gets you a chance to test drive the Mark VIII. I think the choice is obvious (then again, I'm a HUGE Iron Man fan, so...)


	3. Chapter 3

And then Steve was in free fall.

Now, Steve knew that Loki's plan more than likely did not include his death, but the panic that occurs in any sane person falling from more than a thousand feet at 9.8 meters per second per second still coiled up in his stomach and turned his blood to ice.

He spread his arms and legs to get what little resistance he could on his way to becoming a blood spat on the sidewalk.

Now he really wishes he could fly.

Unfortunately, the serum did not see fit to give him wings, so as he neared the pavement, he prayed desperately that whatever Loki was counting on would _hurry the hell up!_

The sidewalk filled his vision in seconds and he closed his eyes, bracing for impact.

So he didn't see the blur of red and gold that swooped underneath him and lifted him when he was mere feet from the ground.

But he definitely felt it.

His eyes flew open as he felt something lifting him. Thankfully, he wasn't dead. That was a pleasant surprise.

The pair of Avengers flew across the street and landed on a small rooftop across the street from the Tower. Steve dropped lightly to the ground as Iron Man landed next to him, flipping his mask open, the same cocky grin as usual curling his lip.

"Need some help, Capsicle?"

Steve plays along. "Nah, just practicing my Parkour." Parkour is one of the few hobbies Steve has picked up since he'd woken from the ice. It tested his strength and helped him think.

Stark chuckled. "Remind me never to go with you, Rogers. That's just a little hardcore without having a flying suit."

His voice suddenly adopts a serious tone.

"Seriously, though, what'd you say to make Reindeer Games decide it'd be fun to teach you what, 'defenestration,' means?"

"Not much, actually. He went on the whole, 'You will never defeat me," cliche supervillain monologue, and when I said we would Avenge the Earth even if we couldn't stop him... well, he got a little pissed." Well, that was a half-truth. Sort of.

"Ah."

For a moment there's an uncomfortable silence.

"So, Tony," starts Steve, as if this is a spur-of-the-moment question. "In case of an emergency, how do we get you out of your suit?"

Tony smirks. "Already so eager to get me undressed, Cap?"

Steve turns faintly red in the cheeks, and Tony decides to grace his question with a real answer.

"Hopefully there won't be an emergency, but if there is, there's a disassemble button on my left ankle. Please don't push it unless you have to, though, because it won't go back together afterwards."

"Got it," Steve says, masking the satisfaction he feels.

Just then, a loud crack is heard from Stark Tower. A shaft of pure blue light shoots into the sky, and all the people on the streets look up curiously. Their curiosity quickly morphs into suspicion, then terror as a small swarm of Chitauri come flying through the newly-opened portal.

"Oh. There's the army," quips Stark lowering his faceplate. His repulsor beams power up as he shoots off towards the portal. He manages to hit several Chitauri, but for every one he disables, three more fly out of the portal.

Still, only about a hundred of them fly out altogether, just enough to pose a threat, but nowhere near a fraction of the actual size of their forces.

Steve hears Agent Romanoff, three stories below, say something along the lines of, "That's an army? Budapest was worse than this."

He smirks. Oh, the naivety. That will soon be remedied, however.

He squints slightly against the harsh glare of the sun as he peers across the street to Stark Tower, where Loki stands on the balcony, watching the chaos below his feet with satisfaction.

He catches the god's eye, and Loki cocks an eyebrow at him. There's a flash of light and a squeezing and then he's beside Loki. Luckily, no one is paying attention to the god when there's a swarm of aliens invading New York, so no one notices the second figure appearing beside him.

"Well?" prompts Loki.

"I can take down Stark and the Hulk. Maybe Barton as well, though it'd be hard to approach him, considering how he likes to perch on rooftops."

Sure enough, an arrow shoots out from a nearby rooftop towards an oncoming Chitauri warrior, sending it plummeting to the ground.

"Take down Barton first. I have a promise to keep with a certain redhead."

Steve remembers the footage from Loki and Romanoff's talk back in the helicarrier. "Sir?" he says, slightly worried about Loki killing her.

"Oh, I won't kill her, not yet. Just make her watch helplessly as I turn Barton yet again.

Steve quickly quashes a momentary jolt of guilt. "How would you prefer for me to take him down?"

"Here," Loki says, waving his hand absently. Suddenly the soldier is encased in armor, a perfect replica of Stark's Mark VII.

"I'm sure you can do the rest, Rogers."

"Yes, sir."

With that, there is a flash and Steve is again standing on the opposite rooftop.

He lowers the faceplate, taking a moment to adjust to the new focus required to watch the multiple screens, then takes off towards Barton, silhouetted against the blue sky, now marred by alien cyborgs falling from the clouds.


End file.
